<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>Document</title>
		<style type="text/css">
			.box1{
				border:10px red solid;				
			}
			.box2{
				width: 100px;
				height: 300px;
				background-color: #7FFFD4;
				float: left;/* 向左浮动 */
			}
			.box3{
				clear:both;/* 消除左右两侧浮动影响 */
			}			
		</style>
	</head>
	<body>
		<div class="box1">
			<div class="box2">				
			</div>
			<div class="box3">				
			</div>			
		</div>
	</body>
</html>
